From 7f15b66468b7003d5241e352a007e73be5519b20 Mon Sep 17 00:00:00 2001 From: "R.Marek@sh.cvut.cz" Date: Thu, 26 May 2005 12:42:19 +0000 Subject: [PATCH] I2C: documentation update 2/3 This patch adds missing documentation for system health monitoring chips. I would like to thank all people, who helped me with this project. Signed-off-by: Rudolf Marek Signed-off-by: Greg Kroah-Hartman --- Documentation/i2c/chips/fscher | 169 +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 169 insertions(+) create mode 100644 Documentation/i2c/chips/fscher (limited to 'Documentation/i2c/chips/fscher') diff --git a/Documentation/i2c/chips/fscher b/Documentation/i2c/chips/fscher new file mode 100644 index 00000000000..64031659aff --- /dev/null +++ b/Documentation/i2c/chips/fscher @@ -0,0 +1,169 @@ +Kernel driver fscher +==================== + +Supported chips: + * Fujitsu-Siemens Hermes chip + Prefix: 'fscher' + Addresses scanned: I2C 0x73 + +Authors: + Reinhard Nissl based on work + from Hermann Jung , + Frodo Looijaard , + Philip Edelbrock + +Description +----------- + +This driver implements support for the Fujitsu-Siemens Hermes chip. It is +described in the 'Register Set Specification BMC Hermes based Systemboard' +from Fujitsu-Siemens. + +The Hermes chip implements a hardware-based system management, e.g. for +controlling fan speed and core voltage. There is also a watchdog counter on +the chip which can trigger an alarm and even shut the system down. + +The chip provides three temperature values (CPU, motherboard and +auxiliary), three voltage values (+12V, +5V and battery) and three fans +(power supply, CPU and auxiliary). + +Temperatures are measured in degrees Celsius. The resolution is 1 degree. + +Fan rotation speeds are reported in RPM (rotations per minute). The value +can be divided by a programmable divider (1, 2 or 4) which is stored on +the chip. + +Voltage sensors (also known as "in" sensors) report their values in volts. + +All values are reported as final values from the driver. There is no need +for further calculations. + + +Detailed description +-------------------- + +Below you'll find a single line description of all the bit values. With +this information, you're able to decode e. g. alarms, wdog, etc. To make +use of the watchdog, you'll need to set the watchdog time and enable the +watchdog. After that it is necessary to restart the watchdog time within +the specified period of time, or a system reset will occur. + +* revision + READING & 0xff = 0x??: HERMES revision identification + +* alarms + READING & 0x80 = 0x80: CPU throttling active + READING & 0x80 = 0x00: CPU running at full speed + + READING & 0x10 = 0x10: software event (see control:1) + READING & 0x10 = 0x00: no software event + + READING & 0x08 = 0x08: watchdog event (see wdog:2) + READING & 0x08 = 0x00: no watchdog event + + READING & 0x02 = 0x02: thermal event (see temp*:1) + READING & 0x02 = 0x00: no thermal event + + READING & 0x01 = 0x01: fan event (see fan*:1) + READING & 0x01 = 0x00: no fan event + + READING & 0x13 ! 0x00: ALERT LED is flashing + +* control + READING & 0x01 = 0x01: software event + READING & 0x01 = 0x00: no software event + + WRITING & 0x01 = 0x01: set software event + WRITING & 0x01 = 0x00: clear software event + +* watchdog_control + READING & 0x80 = 0x80: power off on watchdog event while thermal event + READING & 0x80 = 0x00: watchdog power off disabled (just system reset enabled) + + READING & 0x40 = 0x40: watchdog timebase 60 seconds (see also wdog:1) + READING & 0x40 = 0x00: watchdog timebase 2 seconds + + READING & 0x10 = 0x10: watchdog enabled + READING & 0x10 = 0x00: watchdog disabled + + WRITING & 0x80 = 0x80: enable "power off on watchdog event while thermal event" + WRITING & 0x80 = 0x00: disable "power off on watchdog event while thermal event" + + WRITING & 0x40 = 0x40: set watchdog timebase to 60 seconds + WRITING & 0x40 = 0x00: set watchdog timebase to 2 seconds + + WRITING & 0x20 = 0x20: disable watchdog + + WRITING & 0x10 = 0x10: enable watchdog / restart watchdog time + +* watchdog_state + READING & 0x02 = 0x02: watchdog system reset occurred + READING & 0x02 = 0x00: no watchdog system reset occurred + + WRITING & 0x02 = 0x02: clear watchdog event + +* watchdog_preset + READING & 0xff = 0x??: configured watch dog time in units (see wdog:3 0x40) + + WRITING & 0xff = 0x??: configure watch dog time in units + +* in* (0: +5V, 1: +12V, 2: onboard 3V battery) + READING: actual voltage value + +* temp*_status (1: CPU sensor, 2: onboard sensor, 3: auxiliary sensor) + READING & 0x02 = 0x02: thermal event (overtemperature) + READING & 0x02 = 0x00: no thermal event + + READING & 0x01 = 0x01: sensor is working + READING & 0x01 = 0x00: sensor is faulty + + WRITING & 0x02 = 0x02: clear thermal event + +* temp*_input (1: CPU sensor, 2: onboard sensor, 3: auxiliary sensor) + READING: actual temperature value + +* fan*_status (1: power supply fan, 2: CPU fan, 3: auxiliary fan) + READING & 0x04 = 0x04: fan event (fan fault) + READING & 0x04 = 0x00: no fan event + + WRITING & 0x04 = 0x04: clear fan event + +* fan*_div (1: power supply fan, 2: CPU fan, 3: auxiliary fan) + Divisors 2,4 and 8 are supported, both for reading and writing + +* fan*_pwm (1: power supply fan, 2: CPU fan, 3: auxiliary fan) + READING & 0xff = 0x00: fan may be switched off + READING & 0xff = 0x01: fan must run at least at minimum speed (supply: 6V) + READING & 0xff = 0xff: fan must run at maximum speed (supply: 12V) + READING & 0xff = 0x??: fan must run at least at given speed (supply: 6V..12V) + + WRITING & 0xff = 0x00: fan may be switched off + WRITING & 0xff = 0x01: fan must run at least at minimum speed (supply: 6V) + WRITING & 0xff = 0xff: fan must run at maximum speed (supply: 12V) + WRITING & 0xff = 0x??: fan must run at least at given speed (supply: 6V..12V) + +* fan*_input (1: power supply fan, 2: CPU fan, 3: auxiliary fan) + READING: actual RPM value + + +Limitations +----------- + +* Measuring fan speed +It seems that the chip counts "ripples" (typical fans produce 2 ripples per +rotation while VERAX fans produce 18) in a 9-bit register. This register is +read out every second, then the ripple prescaler (2, 4 or 8) is applied and +the result is stored in the 8 bit output register. Due to the limitation of +the counting register to 9 bits, it is impossible to measure a VERAX fan +properly (even with a prescaler of 8). At its maximum speed of 3500 RPM the +fan produces 1080 ripples per second which causes the counting register to +overflow twice, leading to only 186 RPM. + +* Measuring input voltages +in2 ("battery") reports the voltage of the onboard lithium battery and not ++3.3V from the power supply. + +* Undocumented features +Fujitsu-Siemens Computers has not documented all features of the chip so +far. Their software, System Guard, shows that there are a still some +features which cannot be controlled by this implementation. -- cgit v1.2.3